As a method of measuring a speed of a moving body, a Doppler method that transmits an electromagnetic wave as a transmission wave from an antenna and calculates the speed of the moving body from a frequency variation between the transmission wave and a reflected wave from the moving body is widely known.
As a speed measuring device for a moving body that uses the Doppler method, a measuring device for a head speed of a golf club head, for example, has been proposed (see Japanese Unexamined Patent Application Publication Nos. 2006-326318A and 2008-246139A).
These conventional devices are configured by incorporating an antenna, which transmits the transmission wave toward the golf club head that is the moving body and receives the reflected wave from the moving body, and a display into a unitary housing.
In the Doppler method, it is important that a transmission direction of the transmission wave and a movement direction of the moving body match as much as possible to ensure measurement accuracy.
Therefore, a layout of the antenna and the display is configured so that, in a state where the housing is installed so that an orientation direction of the antenna is parallel to the movement direction of the golf club head, a user can easily see display contents (head speed and the like) of the display.
Specifically, an installation location of the housing of the speed measuring device is a location on the ground behind a ball to be struck by the golf club head or a location on the ground to a side of the ball that does not interfere with swinging, and the display faces upward or obliquely upward so that the user who swings the golf club can easily view the display of the speed measuring device.
Incidentally, it is also conceivable to measure, for example, a speed of a ball when pitching a baseball or a swing speed when swinging a baseball bat using such a speed measuring device for a moving body.
In these situations, it is preferred that the speed measuring device is disposed in a location away from the ground and in front of the user by supporting the speed measuring device using a stand or the like so that the orientation direction of the antenna matches a movement direction of the ball or a movement direction of the bat as much as possible.
However, disposing the speed measuring device in this manner causes the display to face upward or obliquely upward, and it becomes difficult for the user behind the speed measuring device to view the display. Because of this, the user must approach the speed measuring device to see the display each time speed measurement is implemented, which decreases usability.
Furthermore, if the speed measuring device is installed with a direction of the display set to be easily seen by the user, the orientation direction of the antenna and the movement direction of the moving body no longer match, and measurement accuracy of a movement speed decreases.